High speed router for aluminium tooling 3d profiling.

Been thinking about adding a small high speed milling spindle to the side of a denford triac or emco mill 50 to create a nice little unit for making small aluminium moulds.

The alternative is to push the orignial spindle past it's comfort zone with a new vfd and and motor/pulleys, but I'm not sure how practical this would be. For small alu ballnoses sub 1mm high speed spindle are prob going to be a must. I would imagine 24,000 rpm would be ideal but the emco for example only hits about 3000 max. Will the bearings take it?

has anyone seen this done on a mini mill? Travel across the bed is going to be the limiting factor. I am going to have to get the spindle as close to the centre of the main spindle as possible.

here are a few examples

CNC Cookbook: Add-On High Speed Spindles

the larger the machine the easier this would be, rigidity I can only imagine would not be critical due to the fact the tiny ball mills are more likely to bend first before a spindle mount will?

What about something like this ? it only goes to 12000 rpm but a further search would likely find a 24000 model

CNC 400W Spindle Motor ER11 & Mach3 PWM speed controller & Mount engraving set | eBay

Why don't you use a brushless RC motor and make your own spindle? I have but mine won't do that sort of speed as I want it for cutting wood and Ali. It's about 1.7kW I think at max power. Search for "DIY brushless spindle" and you'll find BlackburnMarks thread. If you want it at about 24000 rpm then running it at 24V you'll need at least a 1000kV motor which is a very common size.

Or maybe just belt drive an ER11 secondary spindle off the main spindle with 1:8 gearing?

Why can't you do this with your Thermwood? Make a fixture that will contain any coolant etc. To grip the small dia. tools in my SCM I use an ER 16 straight shank (20mm) collet chuck gripped in the ER 32 collet. Just a thought. G

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Originally Posted by GEOFFREY

Why can't you do this with your Thermwood? Make a fixture that will contain any coolant etc. To grip the small dia. tools in my SCM I use an ER 16 straight shank (20mm) collet chuck gripped in the ER 32 collet. Just a thought. G

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I think it would def be worth a shot. Have you tried 3d profiling with your SCM. Did you find the Collet chuck added any extra run out?

Thermwood takes it gcode in floppy disc sized chunks and there is apparently no way around the 1.4mb file limit. So for large files I have to break it down into smaller parts, it works but might limit its ability to use a super fine step over to obtain a nice smooth finish.

I am afraid that I have not done any 3d work yet (can,t draw!!!), But I do regularly use small cutters and do not have any problems with runout. The SCM also used floppy discs, but I had the NUM controller upgraded (by NUM) to USB and can in anycase "drip feed" larger programs. What controller does the Thermwood use? G.

The Thermwood controller is made by Thermwood themselves, they call it the supercontroller 91000 or 910000. It is similer to a mach 3 setup with a motioncontroller like a kflop board. The controller is very nice to use and I would be sad to see it go, but one day it is going to go pop and I will convert it to mach 3/kflop/linux cnc rather than spend thousands on the parts needed to repair, in fact most parts are prob not available.

My machine is from 1997 I think, had it been a couple of years younger I would have been able to load files onto the hard drive via a local network and that would have solved that issue, but to be honest this machine is made to profile plywood shapes and most files for simple 2d stuff come well under 1.4mb. 3d wise I have made a series of 1.2m boat hulls on this machine from foam insulating board the widest boat was just under 300mm so 150mm per halve. It did a fine job of that so I think there would be a argument for converting it to mach 3 and squeesing a bit more versatililty out of her.